This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. A chapter was submitted for the new book, Multifrequency EPR:Theory and Applications, Editor Sushil Misra (Wiley-VCH). Chapter 15 "Biological Systems" shows applications of High Field ESR (VHF EPR) for biological systems and discusses in details the virtues of High Field multifrequency ESR compared to standard ESR at lower frequency.